JP2022043885A - Inkjet ink and tablet - Google Patents

Abstract

To provide: an inkjet ink that sufficiently suppresses fading and changing of colors in a print image caused by light and that has excellent light resistance; and a tablet provided with a print part that is printed with the inkjet ink.SOLUTION: The inkjet ink contains: blue no. 1 as an edible dye; a disaccharide, as a binder, having a solubility in the range from 20 g to 39 g inclusive in 100 ml of water at 20°C; and, as a solvent, water and propylene glycol and/or ethanol.SELECTED DRAWING: None

Description

The present invention relates to inkjet inks and tablets.

Some inkjet printing inks (hereinafter, also simply referred to as “inkjet inks”) have edible properties by using an edible dye such as a tar-based dye as a coloring material.
Conventionally, some inkjet inks cause discoloration in which the color tone (color tone) of the color material changes in printed characters, images, etc. due to deterioration of the color material, and fading due to a decrease in saturation of the color material. For example, when the light resistance of an inkjet ink is insufficient, fading (light fading) may occur due to decomposition (photodecomposition) of the coloring material by the action of light. Such discoloration is recognized as a decrease in visibility in printed characters, images, and the like (hereinafter collectively referred to as "printed images").

Techniques are being developed to suppress such discoloration of printed images, and various methods for suppressing discoloration have been proposed (for example, Patent Document 1). However, the conventional method does not sufficiently suppress the light fading of the printed image, and the light resistance of the inkjet ink cannot be improved.

Japanese Patent No. 6389506

The present invention has been made in view of these respects, and provides an inkjet ink having sufficiently suppressed photo-fading of a printed image and improved light resistance, and a tablet provided with a printing portion printed with the inkjet ink. The purpose is to do.

In order to achieve the above object, the inkjet ink according to one aspect of the present invention contains Blue No. 1 as an edible dye and has a solubility of 20 g or more and 39 g or less in 100 ml of water at 20 ° C. as a fixing agent. It contains a disaccharide and is characterized by containing water and at least one of propylene glycol and ethanol as a solvent.

Further, in order to achieve the above object, the tablet according to one aspect of the present invention is characterized by including a printing unit printed using the inkjet ink.

According to one aspect of the present invention, it is possible to sufficiently suppress the light discoloration of the printed image and improve the light resistance of the inkjet ink.

It is a conceptual diagram explaining the permeability and light resistance of the inkjet ink in embodiment of this invention. It is a schematic sectional drawing which shows an example of the tablet (bare tablet) which concerns on embodiment of this invention. It is a schematic sectional drawing which shows an example of the tablet (film-coated tablet) which concerns on embodiment of this invention. This is an example of a printed image of a tablet (uncoated tablet) according to an embodiment of the present invention. This is an example of a printed image of a tablet (film-coated tablet) according to an embodiment of the present invention.

The inkjet ink according to an embodiment of the present invention (hereinafter referred to as "the present embodiment") sufficiently suppresses light fading of a printed image or the like applied to the surface of a medical tablet by an inkjet printing method, and is light resistant. It relates to an inkjet ink that can improve the properties. Hereinafter, the configuration of the inkjet ink according to the embodiment of the present invention and the tablet provided with the printing unit printed with the inkjet ink will be described in detail.

[Composition of inkjet ink]
The inkjet ink according to the present embodiment is an edible inkjet ink and contains edible blue No. 1 (hereinafter, simply referred to as "blue No. 1") as an edible dye (edible dye). Further, the inkjet ink according to the present embodiment contains a saccharide whose solubility in water satisfies a predetermined condition as a fixing agent for fixing the ink to the surface of a printed matter (for example, a solid preparation). Specifically, in the present embodiment, a disaccharide having a solubility in 100 ml of water at 20 ° C. of 20 g or more and 39 g or less is used as the fixing agent. Further, the inkjet ink according to the present embodiment contains water and at least one of propylene glycol and ethanol as a solvent. According to such a configuration, it is possible to sufficiently suppress the light fading of the printed image and improve the light resistance of the inkjet ink. Hereinafter, this point will be described with reference to FIG.

FIG. 1 is a conceptual diagram for explaining the relationship between ink sticking on the surface of a printed matter (solid preparation) and light resistance. Here, as the solid preparation, for example, a tablet provided with a film-coated portion having few voids, that is, a film-coated tablet is used. The present invention is not limited to this, and unprinted tablets or capsule tablets may be used as printed matter.

1 (a) to 1 (c) show a cross section in the thickness direction of a tablet in which inkjet inks A to C having different compositions are printed on a tablet (here, a film-coated tablet) and allowed to elapse for a certain period of time. It is a schematic diagram. In this example, the inkjet ink A is an ink in which the specific dye 4 is used as the coloring material and water is used as the solvent. Here, the specific dye 4 may contain Blue No. 1. Further, the inkjet ink B is an ink obtained by adding a predetermined saccharide to the inkjet ink A. Here, the saccharide added to the inkjet ink B is a saccharide (for example, maltose) which has a relatively high solubility in water and does not correspond to the fixing agent in the present embodiment. Further, the inkjet ink C is an ink in which a disaccharide corresponding to the fixing agent is added to the inkjet ink A, and at least one of propylene glycol and ethanol is added to water as a solvent.

Specifically, in FIG. 1A, an inkjet ink A containing a specific dye 4 as a coloring material and water as a solvent is printed on the surface 1S of the base material 1 of a tablet for a certain period of time (for example, 140 hours). ) It is a schematic cross-sectional view in the thickness direction of the tablet in the aged state. Further, FIG. 1B is a schematic cross-sectional view in the thickness direction of the tablet in a state where the inkjet ink B is printed on the surface 1S of the base material 1 of the tablet and a certain period of time (for example, 140 hours) has elapsed. Further, FIG. 1 (c) is a schematic cross-sectional view in the thickness direction of the tablet in a state where the inkjet ink C is printed on the surface 1S of the base material 1 of the tablet and a certain period of time (for example, 140 hours) has elapsed.

First, the presence or absence of saccharides added to the inkjet ink and the permeability of the dye will be described by taking inkjet inks A and B as examples.
Of the various coloring materials used in inkjet inks, for example, tar-based dyes used as edible dyes may cause discoloration in characters, images, and the like printed on the surface of solid preparations and the like. For example, among the tar-based dyes, Blue No. 1 caused discoloration of the printed image due to permeation into the solid preparation over time and photodecomposition. On the other hand, there is known a method of suppressing the permeation of a dye into a solid preparation and suppressing the discoloration of a printed image by adding a saccharide to the inkjet ink.

As shown in FIG. 1A, when the inkjet ink A containing no saccharide is printed, the specific dye 4 permeates the inside of the base material 1 of the tablet after a certain period of time has passed from the printing. Here, the penetration depth of the specific dye 4 in the inkjet ink A after the lapse of a certain period of time is defined as the penetration depth X (μm). On the other hand, as shown in FIG. 1 (b), when the inkjet ink B containing saccharides is printed, the penetration depth Y (μm) of the inkjet ink B is the same as that of the inkjet ink A after a lapse of a certain period of time from printing. It is smaller than the penetration depth X (X> Y).

In the inkjet ink B, the addition of a predetermined saccharide causes an increase in the viscosity of the ink and the like, and the penetration of the specific dye 4 into the base material 1 of the tablet is suppressed. Therefore, when the inkjet ink B is printed, the specific dye 4 remains in the vicinity of the surface 1S in the base material 1 of the tablet even after a certain period of time has elapsed from the printing. That is, the inkjet ink containing a predetermined saccharide can suppress the discoloration of the printed image due to the penetration of the dye (for example, Blue No. 1) as compared with the case where the saccharide is not added. On the other hand, the inkjet ink B to which a predetermined sugar is added cannot sufficiently suppress the discoloration (light discoloration) of the printed image due to light irradiation.

On the other hand, in the inkjet ink according to the present embodiment, the ink is adhered to the surface of the printed matter by selecting the type and physical properties of the saccharide and the solvent to be added, and the light discoloration of the printed image is sufficiently suppressed. , It improves the light resistance. The present inventors have found that it is effective to fix ink on the surface of a printed matter (for example, a tablet) in order to suppress light discoloration of a printed image. In this example, by fixing the ink on the surface 1S of the tablet, the specific dye 4) is fixed on the surface 1S, and as a result, the specific dye 4 can be left on the surface 1S at a high concentration.

When the concentration of the specific dye 4 is high on the surface 1S of the base material 1 of the tablet, for example, the proportion of the color material that causes photodiscoloration due to photodecomposition in the specific dye 4 on the surface 1S is reduced. That is, even if light discoloration occurs in a part of the specific dye 4, the influence is limited, and the deterioration of the visibility (readability) of the printed image is suppressed. As a result, the visibility of the printed image as a whole is maintained, and as a result, the light discoloration of the printed image can be sufficiently suppressed. Therefore, the light resistance of the inkjet ink can be improved. Then, the present inventors have discovered that a disaccharide having a relatively low solubility in water among saccharides functions as a fixing agent for adhering an ink containing Blue No. 1 as a coloring material to the surface of a printed matter. Furthermore, the present inventors have discovered that with respect to the above disaccharide used as a fixing agent, the fixing effect of the ink is surely exhibited by reducing the solubility in a solvent.

Specifically, the inkjet ink according to the present embodiment contains blue No. 1 as a coloring material and an edible dye, disaccharide having a solubility in the range of 20 g or more and 39 g or less as a fixing agent, and water as a solvent. And at least one of propylene glycol or ethanol. According to such a configuration, an ink containing a specific tar-based dye used as a coloring material (blue No. 1 in this example) is fixed to the surface of the printed matter, and the specific tar-based dye is concentrated on the surface. Can be left with. As a result, the inkjet ink according to the present embodiment can sufficiently suppress the light fading of the printed image and improve the light resistance.

As shown in FIG. 1 (c), when the inkjet ink C corresponding to the inkjet ink according to the present embodiment is printed on the surface 1S of the base material 1 of the tablet, the specific dye 4 in the ink (here, blue No. 1) is printed. Is fixed to the surface 1S. Specifically, when the inkjet ink C is printed, the penetration depth Z (μm) of the specific dye 4 after a lapse of a certain period of time from the printing is the penetration depth Y of the specific dye 4 in the inkjet ink B containing a predetermined saccharide. It is further reduced (Y> Z). For example, the penetration depth Z of the specific dye 4 in the inkjet ink C is reduced to about 50% of the penetration depth Y of the specific dye 4 in the inkjet ink B. That is, the inkjet ink C can further suppress the penetration of the specific dye 4. Therefore, the specific dye 4 remains on the surface 1S at a high concentration, and the deterioration of the visibility of the printed image is suppressed as described above. As a result, the light fading of the printed image is sufficiently suppressed, and the inkjet ink C can improve the light resistance.

On the other hand, although the inkjet ink B can leave the specific dye 4 in the vicinity of the surface 1S inside the base material 1 of the tablet, the permeation of the specific dye 4 is not sufficiently suppressed and the ink is fixed on the surface 1S. It is not possible. That is, in the inkjet ink B, since the concentration of the specific dye 4 remaining on the surface 1S is low, the light discoloration of the printed image cannot be sufficiently suppressed, and the light resistance is not improved (improved).

As described above, in the inkjet ink according to the present embodiment, the above disaccharide is added as a fixing agent, and the solvent is further composed of the above components, so that a specific tar-based dye (blue No. 1) can be applied to the inside of the printed matter. Penetration is greatly suppressed and the ink is fixed to the surface of the printed matter. As a result, the inkjet ink according to the present embodiment can suppress the light discoloration of the printed image and improve the light resistance, and further, the printed image due to the permeation of the specific tar-based dye into the inside of the printed matter. Discoloration can also be suppressed.

Further, as shown in FIG. 1 (c), the inkjet ink C can be fixed on the surface 1S of the base material 1 of the tablet so as to be slightly raised. As a result, for example, when the inkjet ink C is printed, it is recognized that the print is deeply embossed on the surface 1S. Therefore, compared to, for example, the inkjet inks A and B, the inkjet ink C can improve the visibility of the printed image at the time of printing. That is, in the inkjet ink according to the present embodiment, in addition to reducing the deterioration of visibility due to light fading of the printed image, it is possible to impart good visibility to the printed image at the time of printing.

Hereinafter, the details of the light resistance of the inkjet ink according to the present embodiment will be described.
The inkjet ink according to this embodiment may have a color difference ΔE of 15 or less in JIS Z 8781 before and after the light resistance test. Here, the light resistance test is, for example, a color difference ΔE (JIS Z 8781) indicating the amount of change in chromaticity and optical color density before and after irradiation with visible light in a printed image printed using the inkjet ink according to the present embodiment. It is a test to compare (complying with). Specifically, the color difference ΔE is measured before and after irradiating the printed image with a cumulative amount of visible light of 1.2 million lux, and the values are compared. For irradiation of visible light, for example, a xenon weather meter (Ci4000 manufactured by Toyo Seiki Seisakusho) is used. Further, the printed image in the light resistance test is, for example, a solid print on a tablet (for example, a film-coated tablet) which is an object to be printed.

The necessary and sufficient light resistance for forming a printed image on medical tablets, etc. means that the color difference ΔE of the printed image before and after irradiation with visible light may indicate 15 or less in a light resistance test in which visible light of 1.2 million lux is irradiated. many. The fact that the color difference ΔE is 15 or less as a criterion for sufficient light resistance was derived as a result of the opinion test conducted by the inventors with each medical personnel, and the color difference ΔE is 15. If it exceeds the limit, it will be recognized that the visibility of the printed image (for example, the readability of the print) is deteriorated. That is, when the color difference ΔE before and after irradiation with visible light is 15 or less, it can be said that the inkjet ink has excellent light resistance with sufficient suppression of light fading. Although the number is larger than 3 to 6, which is a guideline for the color difference ΔE in general commercial printed matter, usually, tablets before and after exposure are not compared, and the printed image on the tablet surface is natural. I was able to get this number because it was supposed to fade.

In the inkjet ink according to the present embodiment, the reason why the disaccharide satisfying the condition that the solubility in 100 ml of water at 20 ° C. is 20 g or more and 39 g or less is used as the fixing agent and the solvent having the above-mentioned composition is used does not satisfy the above-mentioned condition. When a saccharide (for example, maltose having a solubility in 100 ml of water at 20 ° C. is 52 g) is added, or when the solvent does not have the above-mentioned component composition, a specific tar-based dye on the tablet surface, that is, Blue No. 1 is on the surface of the printed matter. This is because the color difference ΔE exceeds 15 when the above-mentioned light resistance test is performed on a solid printed image. By adding a disaccharide having a solubility in water satisfying the above conditions as a fixing agent and reducing the solubility of the disaccharide in the solvent by using a solvent satisfying the above component composition, the color difference ΔE is less than 15 before and after the light resistance test. Therefore, excellent light resistance is imparted to the inkjet ink.

Hereinafter, each component constituting the inkjet ink according to this embodiment will be described.
(Color material)
As described above, the inkjet ink according to the present embodiment contains at least Blue No. 1 as an edible dye. Blue No. 1 is an edible tar-based pigment and is also called Brilliant Blue FCF. In the inkjet ink according to the present embodiment, the blending ratio of the edible dye containing the specific tar-based dye (Blue No. 1), that is, the total content of the edible dye is 1% by mass or more with respect to the total mass of the ink 15. It is preferably in the range of mass% or less. With such a configuration, it is possible to impart good visibility to the printed image and to impart high intermittent resumption. Further, if the total content of the edible dye is within the above range, the addition of the fixing agent ensures that the above-mentioned specific tar-based dye remains on the surface of the printed matter at a high concentration, and the photo-discoloration in the printed image is suppressed. However, the light resistance of the inkjet ink according to the present embodiment can be improved.

On the other hand, when the total content of the edible dyes is less than 1% by mass, the entire print color tends to be light and the visibility of the printed image tends to decrease. If the content exceeds 15% by mass, the dye in the ink precipitates or precipitates as a solid due to deterioration of the dissolution stability of the coloring material, which causes clogging of the nozzle of the inkjet head during printing. The so-called print resumption (intermittent resumption) may decrease.

The inkjet ink according to the present embodiment may contain the above-mentioned specific tar-based dye, that is, a dye (coloring material) other than Blue No. 1. The pigments other than Blue No. 1 are not particularly limited as long as they are edible. The dye that can be added to the inkjet ink according to the present embodiment can be appropriately selected and added from, for example, conventionally known synthetic food dyes and natural food dyes. Further, even when the inkjet ink according to the present embodiment contains a coloring material other than the above-mentioned specific tar-based dye as an edible dye, the total content of the edible dye is within the above range (1% by mass or more and 15% by mass or less). It is good. As a result, good visibility can be imparted to the printed image while improving the light resistance of the inkjet ink, and sufficient intermittent resumption can be imparted to the inkjet ink.

Examples of the synthetic food coloring include tar-based pigments, natural pigment derivatives, natural synthetic pigments and the like. Examples of tar-based pigments include edible red No. 2, edible red No. 3, edible red No. 40, edible red No. 102, edible red No. 104, edible red No. 105, edible red No. 106, edible yellow No. 4, and edible yellow. Edible Blue No. 2, Edible Red No. 2 Aluminum Lake, Edible Red No. 3 Aluminum Lake, Edible Red No. 40 Aluminum Lake, Edible Yellow No. 4 Aluminum Lake, Edible No. 5 Aluminum Lake, Edible Blue No. 1 Aluminum Lake, Edible Blue No. 2 aluminum lake and the like can be mentioned. Examples of the natural dye derivative include norbixine potassium and the like. Examples of the natural synthetic dye include β-carotene, riboflavin and the like.

Examples of natural food dyes include anthocyanin pigments, carotenoid pigments, quinone pigments, chlorophyll pigments, flavonoid pigments, betaine pigments, monascus pigments, and other pigments originating from natural products. Examples of anthocyanin pigments include red daikon pigment, red cabbage pigment, red rice pigment, elderberry pigment, cowberry pigment, gooseberry pigment, cranberry pigment, salmonberry pigment, perilla pigment, shim blueberry pigment, strawberry pigment, and dark sweet. Cherry pigment, cherry pigment, hibiscus pigment, hakuruberry pigment, grape juice pigment, grape skin pigment, black currant pigment, blackberry pigment, blueberry pigment, plum pigment, whittleberry pigment, boysenberry pigment, mulberry pigment, purple sweet potato pigment , Purple sweet potato pigment, purple sweet potato pigment, raspberry pigment, red currant pigment, loganberry pigment, and other anthocyanin pigments. Examples of carotenoid pigments include annatto pigments, gardenia yellow, and other carotenoid pigments. Examples of the quinone-based pigment include cochineal pigments, cicon pigments, lac dyes, and other quinone-based pigments. Examples of flavonoid pigments include safflower yellow pigment, great millet pigment, onion pigment, and other flavonoid pigments. Examples of betaine dyes include beet red dyes. Examples of the Monascus pigment include Monascus pigment and Monascus purpureu. Examples of pigments originating from other natural products include turmeric pigment, harlequin pigment, gardenia red pigment, spirulina blue pigment and the like.

(Fixing agent)
As described above, the inkjet ink according to the present embodiment contains a fixing agent for fixing the ink containing a specific tar-based dye (Blue No. 1) to the surface of the printed matter. Specifically, the fixing agent contained in the inkjet ink according to the present embodiment is a disaccharide having a solubility of 20 g or more and 39 g or less in 100 ml of water at 20 ° C., for example, reduced isomaltulose. The solubility of reduced isomaltulose in 100 ml of water at 20 ° C. is 38 g. If the fixing agent has the above composition, the ink containing the specific tar-based dye can be fixed to the surface of the printed matter by adding the fixing agent to the inkjet ink together with the solvent having the above-mentioned composition. As a result, the inkjet ink according to the present embodiment can sufficiently suppress the light fading of the printed image and improve the light resistance. Further, the disaccharide (for example, reduced isomaltulose) used as a fixing agent in the present embodiment also has a function of suppressing decomposition (photodecomposition) of the inkjet ink by light irradiation. Therefore, it is possible to suppress the occurrence of light discoloration itself.

The blending ratio of the fixing agent in the inkjet ink according to the present embodiment, that is, the total content of the above disaccharides (for example, reduced isomaltulose) is within the range of 1% by mass or more and 20% by mass or less with respect to the total mass of the ink. It is preferable to have. With such a configuration, the ink fixing effect of the disaccharide can be more reliably exhibited, and the light resistance of the inkjet ink can be reliably improved. Further, it is possible to impart high intermittent resumption to the inkjet ink according to the present embodiment.

On the other hand, when the blending ratio of the fixing agent is less than 1% by mass, the fixing effect of the ink can be reduced. Further, when the blending ratio of the fixing agent (reduced isomaltulose) exceeds 20% by mass, the fixing agent in the ink precipitates or precipitates as a solid due to an increase in the viscosity of the ink and deterioration of the dissolution stability of the fixing agent. This may cause the nozzle of the inkjet head to be clogged during printing, and the intermittent resumption may be reduced.

(solvent)
The inkjet ink according to the present embodiment is a solvent (dispersion medium) for dissolving (dispersing) the specific tar dye and the fixing agent in addition to the specific tar dye (Blue No. 1) and the fixing agent. Contains. The inkjet ink according to this embodiment may contain water (for example, purified water) and at least one of propylene glycol and ethanol as a solvent. The solvent in this embodiment may contain water and propylene glycol, water and ethanol, or water, propylene glycol and ethanol.

Sugars have the property of being difficult to dissolve in alcohols. Therefore, in the present embodiment, the inclusion of propylene glycol and ethanol in the solvent reduces the solubility of the disaccharide used as the fixing agent in the solvent. Therefore, in the present embodiment, by adding the solvent containing the alcohols (propylene glycol, ethanol) together with the disaccharide (reduced isomaltulose) as the fixing agent to the inkjet ink, the fixing effect of the ink is surely exhibited. , The above-mentioned specific tar-based dye (blue No. 1 in this example) contained in the ink can be left in a high concentration on the surface of the printed matter (for example, a tablet). As a result, the inkjet ink according to the present embodiment can sufficiently suppress the light fading of the printed image and improve the light resistance.
In addition, propylene glycol functions as a wetting agent, can prevent the ink from drying in the inkjet nozzle, and can impart sufficient intermittent resumption to the ink. Further, since ethanol has high volatility, it is possible to improve the transfer resistance (drying property) of the inkjet ink.

Further, in the inkjet ink according to the present embodiment, the blending ratio of each component of the solvent is not limited, but when the solvent contains propylene glycol, the blending ratio of the propylene glycol, that is, the addition amount of propylene glycol is determined. It is preferably in the range of 2% by mass or more and 40% by mass or less with respect to the total mass of the ink. With such a configuration, the solubility of the fixing agent in the solvent is surely lowered, and the fixing effect of the ink containing the specific tar-based dye is further improved. Therefore, it is possible to impart excellent light resistance to the inkjet ink. Further, the amount of propylene glycol added is more preferably 10% by mass or more. As a result, the solubility of the fixing agent in the solvent is further reduced more reliably, and the fixing effect of the ink containing the specific tar-based dye is further improved, so that the inkjet ink can be imparted with further excellent light resistance.

On the other hand, if the amount of propylene glycol added is less than 2% by mass, the effect of reducing the solubility of the fixing agent in the solvent may be reduced. Further, when the amount of propylene glycol added exceeds 40% by mass, the delay in drying the printed surface on the tablet surface increases, and when the printed tablets come into contact with each other, the undried ink adheres to the other tablet. It may cause problems such as stains (transfer defects).

When ethanol is contained in the solvent, the blending ratio of the ethanol, that is, the amount of ethanol added is preferably in the range of 6.5% by mass or more and 40% by mass or less with respect to the total mass of the ink. With such a configuration, the solubility of the fixing agent in the solvent is surely lowered, and the fixing effect of the ink containing the specific tar-based dye is further improved. Therefore, it is possible to impart excellent light resistance to the inkjet ink.

On the other hand, if the amount of ethanol added is less than 6.5% by mass, the effect of reducing the solubility of the fixing agent in the solvent may be reduced. On the other hand, if the amount of ethanol added exceeds 40% by mass, the ink in the inkjet nozzle dries, which causes nozzle clogging of the inkjet head during printing, which may reduce intermittent resumption.

Further, the inkjet ink according to the present embodiment may further contain at least one of glycerin and isopropyl alcohol as a solvent. Specifically, in the above solvent, either one of glycerin and isopropyl alcohol may be further contained, or both glycerin and isopropyl alcohol may be further contained. Glycerin functions as a wetting agent in the same manner as propylene glycol described above. Further, since isopropyl alcohol has high volatility like the above-mentioned ethanol, it is possible to improve the transfer resistance (drying property) of the inkjet ink. By further adding glycerin and isopropyl alcohol to the solvent in addition to the above components, the light resistance of the inkjet ink can be further improved, and the performance corresponding to each component can be imparted to the inkjet ink. Further, by further containing these components in the solvent, the solubility of the fixing agent in the solvent is more reliably lowered, and the fixing effect of the ink containing the specific tar-based dye can be further improved.

(Inner resin)
The inkjet ink according to this embodiment may contain an internal resin in addition to the above-mentioned dye and solvent. The internal resin that can be added to the inkjet ink according to the present embodiment is an edible and water-soluble powder, paste, or flake-like resin-like substance, and forms a film on the tablet surface by drying after printing. Any substance can be used. Examples of the internal resin include high molecular weight polyethylene glycol (PEG) such as polyvinyl alcohol (PVA), hydroxypropyl cellulose (HPC), hydroxypropyl methyl cellulose (HPMC), polyvinylpyrrolidone (PVP), polyethylene glycol 4000 / polyethylene glycol 1540. ), Cellac resin, methacrylic acid copolymer (product name: Eudragit S100), maltodextrin, erythritol and the like.

(Leveling agent)
The inkjet ink according to this embodiment may contain a leveling agent in addition to the above-mentioned dye, solvent, or internal resin. The leveling agent that can be added to the inkjet ink according to the present embodiment may be any edible and water-soluble surfactant. Examples of the leveling agent include polyglycerin fatty acid ester (eg, distearate decaglycerin Q-182S manufactured by Taiyo Kagaku Co., Ltd., monolauric acid decaglycerin Q-12S manufactured by Taiyo Kagaku Co., Ltd.), and sorbitan fatty acid ester (eg, NIKKOLSL-10 manufactured by Nikko Chemicals Co., Ltd.). ), Sucrose fatty acid ester (eg, DK ester F-110 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), polysorbate (Emazole S-120 series manufactured by Kao Co., Ltd.) and the like.

[Printing method]
The inkjet ink according to this embodiment is not particularly limited in terms of printing method, and can be printed using an inkjet device such as a commercially available inkjet printer. Therefore, the inkjet ink according to this embodiment has a wide range of applications and is very useful. For example, the inkjet ink according to the present embodiment can be printed by a so-called drop-on-demand inkjet device using a piezo element (piezoelectric ceramics) as an actuator, or can be printed by another inkjet device.

Drop-on-demand inkjet devices include, for example, devices and actuators that employ a thermal inkjet device that ejects inkjet ink with the steam pressure generated by instantaneously raising the temperature of a minute heat-generating element to a high temperature (200 to 300 ° C.). Examples include an electrostatic type device that ejects inkjet ink by electrostatically vibrating the ink jet, and a device that employs an ultrasonic method that utilizes the cavitation phenomenon of ultrasonic waves. Further, if the inkjet ink according to the present embodiment has charge performance, it is also possible to use an apparatus adopting a continuous injection type (continuous method).

〔tablet〕
In the present embodiment, the inkjet ink according to the present embodiment may be printed and printed on the surface of a tablet, for example, by using the above-mentioned printing method. That is, the tablet according to the present embodiment may include a printing unit printed using the inkjet ink according to the present embodiment, that is, a printed image. With the inkjet ink according to the present embodiment, for example, the light resistance of a printed image (for example, printed image 3) applied to the surface of a medical tablet by an inkjet printing method can be improved. Hereinafter, the configuration of the tablet including the printed image printed with the inkjet ink according to the embodiment will be described.
The tablet according to this embodiment is, for example, a medical tablet. Here, the "medical tablet" is, for example, an uncoated tablet (bare tablet), a sugar-coated tablet, an enteric coated tablet, an orally disintegrating tablet, and a film coating in which a water-soluble surface layer is formed on the outermost surface of the tablet. It includes tablets and the like.

FIG. 2 is a schematic cross-sectional view showing an example of a printed (printed, printed) medical tablet (uncoated tablet). FIG. 2 shows a plain tablet printed matter 5 in which a printed image 3 such as characters is printed on the upper surface of a tablet base material 1 in a cross-sectional view.
FIG. 3 is a schematic cross-sectional view showing an example of a printed (printed, printed) medical tablet (film-coated tablet). FIG. 3 shows a film-coated tablet printed matter 9 in which a printed image 3 such as characters is printed on the upper surface of a tablet substrate 1 having a film-coated layer 7 formed on its surface in a cross-sectional view.
In the present embodiment, as shown in FIG. 4, a solid image may be printed as the uncoated tablet print image 11, and as shown in FIG. 5, a two-dimensional bar code is printed as the film-coated tablet print image 13. You may.

The active ingredient contained in the medical tablet is not particularly limited. For example, substances effective for the prevention and treatment of various diseases (for example, sleep-inducing action, tranquilizer activity, antibacterial activity, antihypertensive action, anti-angina activity, analgesic action, anti-inflammatory activity, psychiatric stabilizing action, diabetes therapeutic activity, diuretic action). , Anticholinergic activity, antigastric acid hyperactivity, antiepileptic activity, ACE inhibitory activity, β-receptor antagonist or agonist activity, anesthetic activity, appetite suppression activity, antiarrhythmic activity, antidepressant activity, antiblood coagulation activity, antidiarrheal disease activity , Antihistamine activity, antimalaria action, antitumor activity, immunosuppressive activity, anti-Parkinson's disease action, antipsychotic action, anti-platelet activity, antihyperlipidemic action, etc.), Detergency substance, fragrance , But is not limited to substances having a deodorizing action.

If necessary, the tablet according to the present embodiment may contain an active ingredient and a carrier acceptable for its use. For example, in the case of medical tablets, a pharmaceutically acceptable carrier can be blended. As the pharmaceutically acceptable carrier, various conventional organic or inorganic carrier substances are used as the pharmaceutical material, and for example, excipients, lubricants, binders, disintegrants, thickeners and the like are appropriately blended. .. If necessary, additives such as preservatives, antioxidants, colorants, and sweeteners can also be used.

In the present embodiment, a medical tablet has been described as an example as a tablet, but the present invention is not limited to this. The printing target of the inkjet ink according to this embodiment is not particularly limited, and for example, tablets, feeds, fertilizers, cleaning agents, ramune confectionery and other tablets and supplements to be administered to animals other than humans (pets, livestock, poultry, etc.). It may be printed on the surface of various tablets such as foods such as. Further, the inkjet ink according to the present embodiment is not particularly limited in the size of the print target, and can be applied to tablets of various sizes.

(Effect of this embodiment)
(1) The inkjet ink according to this embodiment contains Blue No. 1 as an edible dye.
The fixing agent contains a disaccharide having a solubility in 100 ml of water at 20 ° C. in the range of 20 g or more and 39 g or less, and the solvent contains water and at least one of propylene glycol or ethanol.
With such a configuration, as compared with the prior art, it is possible to sufficiently suppress the light discoloration of the printed image using a specific color material and impart excellent light resistance to the inkjet ink.
(2) The inkjet ink according to the present embodiment contains reduced isomaltulose as a fixing agent.
With such a configuration, as compared with the prior art, it is possible to sufficiently suppress the light discoloration of the printed image using a specific color material and impart excellent light resistance to the inkjet ink.

(3) Further, the inkjet ink according to the present embodiment may further contain at least one of glycerin and isopropyl alcohol as a solvent.
With such a configuration, while imparting excellent light resistance to the inkjet ink as compared with the conventional technique, the performance according to each component of the solvent (improvement of intermittent resumption and improvement of tablet drying property). Can be applied to the ink.

(4) Further, the blending ratio of the edible dye contained in the inkjet ink according to the present embodiment may be in the range of 1% by mass or more and 15% by mass or less with respect to the total mass of the ink.
With such a configuration, it is possible to impart high visibility and intermittent resumption to the inkjet ink while imparting excellent light resistance to the inkjet ink as compared with the prior art.

(5) Further, the blending ratio of the fixing agent contained in the inkjet ink according to the present embodiment may be in the range of 1% by mass or more and 20% by mass or less with respect to the total mass of the ink.
With such a configuration, it is possible to impart intermittent resumption to the inkjet ink while reliably imparting excellent light resistance to the inkjet ink as compared with the prior art.
(6) Further, the inkjet ink according to the present embodiment contains propylene glycol as a solvent, and the amount of the propylene glycol added is within the range of 2% by mass or more and 40% by mass or less with respect to the total mass of the ink. There may be.
With such a configuration, it is possible to impart sufficient intermittent resumption to the inkjet ink while reliably imparting excellent light resistance to the inkjet ink as compared with the prior art.
(7) Further, in the inkjet ink according to the present embodiment, the amount of propylene glycol added may be 10% by mass or more with respect to the total mass of the ink.
With such a configuration, it is possible to impart sufficient intermittent resumption to the inkjet ink while reliably imparting superior light resistance to the inkjet ink as compared with the prior art.
(8) Further, the inkjet ink according to the present embodiment contains ethanol as a solvent, and the amount of the ethanol added is within the range of 6.5% by mass or more and 40% by mass or less with respect to the total mass of the ink. There may be.
With such a configuration, it is possible to impart sufficient drying property to the inkjet ink while reliably imparting excellent light resistance to the inkjet ink as compared with the prior art.
(9) The tablet according to the present embodiment includes a printed image (an example of a printing unit) 3 printed with the above-mentioned inkjet ink.
With such a configuration, as compared with the prior art, it is possible to sufficiently suppress light discoloration in the printed image 3 or the like printed directly on the surface of the tablet or the like, and sufficiently improve the light resistance of the printed image 3. can. Further, edible properties can be imparted to the printed image portion printed on the surface of the tablet.
(10) The tablet according to this embodiment may be a medical tablet.
By using the inkjet ink according to the present embodiment, photo-fading is sufficiently suppressed in the medical tablet, and it is possible to reduce the occurrence of erroneous dispensing and administration due to the deterioration of the visibility of the printed image.

[Example]
Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to any examples.

<Example 1>
Hereinafter, the procedure for preparing the inkjet ink according to Example 1 will be described.
(Manufacturing of inkjet ink)
First, printing ink was prepared. Inkjet ink contains each component of a dye (coloring material), a solvent, and a fixing agent. As the order of preparation, first, a fixing agent was added to the solvent to obtain a transparent base liquid. Then, an edible dye was added to the transparent base liquid. In this way, the ink according to this example was prepared. Hereinafter, various components will be specifically described.

In this example, purified water (ion-exchanged water), propylene glycol and ethanol were used as solvents. Specifically, propylene glycol and ethanol were added to purified water and stirred well to obtain a solvent (mixed solvent). Further, reduced isomaltulose was added as a fixing agent to the above-mentioned solvent, and the mixture was stirred for about 1 hour to obtain a transparent base liquid. Blue No. 1, which is an edible dye, was added to the above-mentioned transparent base liquid as a coloring material to obtain the inkjet ink of Example 1. The blending ratio of Blue No. 1 as a coloring material was 4.0% by mass, the blending ratio of purified water in the solvent was 57.5% by mass, and the blending ratio of propylene glycol with respect to the entire inkjet ink of Example 1. Was 28.0% by mass, the blending ratio of ethanol was 6.5% by mass, and the blending ratio of isomalturose as a fixing agent was 4.0%.

<Example 2>
Purified water and propylene glycol were mixed to obtain a solvent (mixed solvent). The mixing ratio of purified water in the solvent was set to 64.0% by mass with respect to the entire ink. Other than that, the inkjet ink of Example 2 was obtained in the same manner as in Example 1.

<Example 3>
Purified water and ethanol were mixed to obtain a solvent (mixed solvent). The blending ratio of purified water in the solvent was 82.0% by mass and the blending ratio of ethanol was 10.0% with respect to the entire ink. Other than that, the inkjet ink of Example 3 was obtained in the same manner as in Example 1.

<Example 4>
Blue No. 1 and Red No. 102 were used as the coloring materials. The blending ratios of Blue No. 1 and Red No. 102 were set to 4.0% by mass with respect to the total ink, and the blending ratios of the coloring materials were set to 8.0% by mass in total. Further, the constituent components of the solvent (mixed solvent) were the same as in Example 1, and the blending ratio of purified water was 53.5% by mass with respect to the entire ink. Other than that, the inkjet ink of Example 4 was obtained in the same manner as in Example 1.

<Example 5>
The blending ratio of Blue No. 1, which is a coloring material, was set to 15.0% by mass with respect to the entire ink. Further, the constituent components of the solvent (mixed solvent) were the same as in Example 1, and the blending ratio of purified water was 46.5% by mass with respect to the entire ink. Other than that, the inkjet ink of Example 5 was obtained in the same manner as in Example 1.

<Example 6>
The blending ratio of Blue No. 1, which is a coloring material, was 1.0% by mass with respect to the entire ink. Further, the constituent components of the solvent (mixed solvent) were the same as in Example 1, and the blending ratio of purified water was 60.5% by mass with respect to the entire ink. Other than that, the inkjet ink of Example 6 was obtained in the same manner as in Example 1.

<Example 7>
The constituent components of the solvent (mixed solvent) were the same as in Example 1, and the blending ratio of purified water was 60.5% by mass with respect to the entire ink. Further, the blending ratio of reduced isomaltulose, which is a fixing agent, was set to 1.0% by mass with respect to the entire ink. Other than that, the inkjet ink of Example 7 was obtained in the same manner as in Example 1.
<Example 8>
The constituent components of the solvent (mixed solvent) were the same as in Example 1, and the blending ratio of purified water was 41.5% by mass with respect to the entire ink. Further, the blending ratio of reduced isomaltulose, which is a fixing agent, was set to 20.0% by mass with respect to the entire ink. Other than that, the inkjet ink of Example 8 was obtained in the same manner as in Example 1.
<Example 9>
The constituent components of the solvent (mixed solvent) were the same as in Example 2, and the blending ratio of purified water was 82.0% by mass and the blending ratio of propylene glycol was 10.0% by mass with respect to the entire ink. Other than that, the inkjet ink of Example 9 was obtained in the same manner as in Example 1.

<Example 10>
The constituent components of the solvent (mixed solvent) were the same as in Example 3, and the blending ratio of purified water was 90.0% by mass and the blending ratio of propylene glycol was 2.0% by mass with respect to the entire ink. Other than that, the inkjet ink of Example 10 was obtained in the same manner as in Example 1.
<Example 11>
The constituent components of the solvent (mixed solvent) were the same as in Example 3, and the blending ratio of purified water was 85.5% by mass and the blending ratio of ethanol was 6.5% by mass with respect to the entire ink. Other than that, the inkjet ink of Example 11 was obtained in the same manner as in Example 1.
<Example 12>
Purified water, glycerin, ethanol and isopropyl alcohol were mixed to obtain a solvent (mixed solvent). The mixing ratio of purified water in the solvent is 57.0% by mass, the mixing ratio of glycerin is 20.0%, the mixing ratio of ethanol is 10.0% by mass, and the mixing ratio of isopropyl alcohol with respect to the entire ink. Was 5.0% by mass. Other than that, the inkjet ink of Example 12 was obtained in the same manner as in Example 1.

<Example 13>
The components of the solvent (mixed solvent) were the same as in Example 2, and the blending ratio of purified water in the solvent was 52.0% by mass and the blending ratio of propylene glycol was 40.0% by mass with respect to the entire ink. bottom. Other than that, the inkjet ink of Example 13 was obtained in the same manner as in Example 1.

<Comparative Example 1>
Blue No. 1 was not added as the coloring material, and Red No. 102 was used. The blending ratio of Red No. 102 was set to 5.0% with respect to the entire ink. Further, the constituent components of the solvent (mixed solvent) are the same as in Example 1, the mixing ratio of purified water in the solvent is 71.5% by mass, and the mixing ratio of propylene glycol is 1.5% by mass with respect to the entire ink. %, And the blending ratio of ethanol was 12.0% by mass. Further, the blending ratio of reduced isomaltulose, which is a fixing agent, was set to 10.0% by mass with respect to the entire ink. Other than that, the inkjet ink of Comparative Example 1 was obtained in the same manner as in Example 1.
<Comparative Example 2>
Red No. 3 was used as the coloring material, and the blending ratio of Red No. 3 was 5.0% by mass with respect to the entire ink. Further, the constituent components of the solvent (mixed solvent) are the same as in Example 1, the mixing ratio of purified water in the solvent is 81.5% by mass, and the mixing ratio of propylene glycol is 1.5% by mass with respect to the entire ink. %, And the blending ratio of ethanol was 12.0% by mass. No saccharides were added. Inkjet ink of Comparative Example 2 was obtained in the same manner as in Example 1 except for the above.
<Comparative Example 3>
Red No. 3 was used as the coloring material, and the blending ratio of Red No. 3 was 5.0% by mass with respect to the entire ink. Inkjet ink of Comparative Example 3 was obtained in the same manner as in Comparative Example 1 except for the above.
<Comparative Example 4>
The constituent components of the solvent (mixed solvent) were the same as in Example 1, and the blending ratio of purified water in the solvent was 61.5% by mass with respect to the entire ink. No saccharides were added. Inkjet ink of Comparative Example 4 was obtained in the same manner as in Example 1 except for the above.
<Comparative Example 5>
Purified water was used alone as a solvent, and the blending ratio of the purified water was 86.0% by mass with respect to the entire ink. Further, the blending ratio of reduced isomaltulose, which is a fixing agent, was set to 10.0% by mass with respect to the entire ink. Other than that, the inkjet ink of Comparative Example 5 was obtained in the same manner as in Example 1.
<Comparative Example 6>
The constituent components of the solvent (mixed solvent) were the same as in Example 1, and the blending ratio of purified water in the solvent was 51.5% by mass with respect to the entire ink. In addition, galactose was added as a saccharide, and the blending ratio was set to 10.0% by mass with respect to the entire ink. Inkjet ink of Comparative Example 6 was obtained in the same manner as in Example 1 except for the above.
<Comparative Example 7>
Maltose was added as a saccharide, and the blending ratio was set to 10.0% by mass with respect to the entire ink. Inkjet ink of Comparative Example 7 was obtained in the same manner as in Comparative Example 6 except for the above.

The solid foreign substances in the liquid were removed by passing each of the inks of Examples 1 to 13 and Comparative Examples 1 to 7 described above through a membrane filter. Specifically, purified ink was obtained by permeating a membrane filter (cellulose acetate film) having a diameter of 5.0 μm once and then passing a membrane filter (cellulose acetate film) having a diameter of 0.8 μm once. ..

<Evaluation>
The light resistance, intermittent resumption property, and tablet drying property of the refined inks obtained from the inks of the Examples and Comparative Examples were evaluated by the following methods. The evaluation results are shown in Tables 1 and 2 described later together with the ink compositions of the above-mentioned Examples and Comparative Examples.

(Light resistance test)
Using a piezoelectric ceramic-driven drop-on-demand inkjet head with a print resolution of 600 dpi in the main scanning direction, 600 dpi in the sub-scanning direction (conveying direction of a recording medium such as a tablet), and a total number of nozzles of 2,656, comparison with Examples 1 to 18 above. Images of the purified inks of Examples 1 to 5 were printed on the following tablets with a print drop amount of 6 pl per drop.
The tablet to be printed was a test film-coated tablet (base: adjusted starch, coating agent: mixture of 70% hydroxypropylmethylcellulose and 30% titanium oxide, diameter: 6.5 mm). The printed image was a circular solid image (diameter 4.0 mm). As a result, a film-coated lock printed matter was obtained.

The film-coated tablet printed matter of each Example and each Comparative Example in which the chromaticity and the optical color density were measured were irradiated with visible light of 1.2 million lux cumulatively using a xenon weather meter (Ci4000, Toyo Seiki Seisakusho). A color difference ΔE (JIS Z 8781) that measures the chromaticity and optical color density of a film-coated tablet printed matter irradiated with visible light with a spectrophotometer and indicates the amount of change in chromaticity and optical color density before and after irradiation with visible light. Compliant ones) were compared. The results of the comparison are shown in Tables 1 and 2. As described above, regarding the change in color before and after irradiation with visible light, as described above, the inventors have found that if the color difference ΔE in JIS Z 8781 is 15 or less (ΔE ≦ 15), the light discoloration is sufficient. It was suppressed to have excellent light resistance. Therefore, if ΔE ≦ 15, it was considered that the inkjet ink has excellent light resistance, and it was judged to be acceptable in this evaluation.

(Intermittent resumption test)
A drop-on-demand inkjet head driven by a piezoelectric ceramic with a print resolution of 600 dpi in the main scanning direction, 600 dpi in the secondary scanning direction (conveying direction of recording media such as tablets), and a total number of nozzles of 2,656 is used for a specified time (15 to 60 minutes). ) After leaving without flushing, a test pattern was printed with a print drop amount of 1 drop and 6 pl, and it was confirmed that all nozzles were able to eject without a non-ejection amount. In Tables 1 and 2 below, as the evaluation result of the intermittent resumption, the leaving time during which the ink can be ejected was measured. The evaluation criteria are as follows.
⊚: 60 minutes or more and less than 120 minutes 〇: 30 minutes or more and less than 60 minutes Δ: 15 minutes or more and less than 30 minutes ×: less than 15 minutes

(Tablet drying resistance (transfer resistance) test)
For the following tablets, a drop-on-demand inkjet head driven by a piezoelectric ceramic having a printing resolution of 600 dpi in the main scanning direction, 600 dpi in the sub-scanning direction (conveying direction of a recording medium such as a tablet), and a total number of nozzles of 2,656 is used, and one drop is 10 pl. Images were printed with the inkjet inks of Examples and Comparative Examples in terms of the amount of print drop.
After 10 seconds of printing, the printed tablets were brought into contact with the white copy paper attached to the digital force gauge at a pressure of 4 to 5 N for 0.4 to 0.5 seconds, and it was confirmed that the printed ink did not transfer. .. In Tables 1 and 2, the concentration of the transferred ink was visually observed as a result of evaluation of transfer resistance (dryness). The evaluation criteria are as follows.
⊚: When there is no ink transfer ○: When the ink transfer is very slight and it is difficult to visually check ×: When the ink is transferred deeply

Table 1 shows the composition and evaluation results of the inkjet inks of each example. Table 2 shows the composition and evaluation results of the inkjet inks of each comparative example. In addition, in Table 1 and Table 2, the part of "blank" indicates that the substance is not used. Further, in Tables 1 and 2, the film-coated lock is abbreviated as "FC lock". Further, in Tables 1 and 2, "solubility in 100 ml of water at 20 ° C." for saccharides is abbreviated as "solubility".

As shown in Table 1, in the film-coated lock printed matter of Examples 1 to 13, as a result of the light resistance test, the color difference ΔE before and after irradiation with visible light was 15 or less (ΔE ≦ 15). Specifically, in the film-coated lock printed matter of Examples 1 to 13, the color difference ΔE before and after irradiation with visible light was in the range of 8 to 14, and all of them were less than 15. That is, it was found that the inkjet inks of Examples 1 to 13 sufficiently suppressed the light fading of the printed image and imparted excellent light resistance. On the other hand, as shown in Table 2, in the film-coated lock printed matter of Comparative Examples 1 to 7, as a result of the light resistance test, the color difference ΔE before and after irradiation with visible light is a value exceeding 15 (ΔE> 15). It became. That is, it was found that the inkjet inks of Comparative Examples 1 to 7 could not sufficiently suppress the light fading of the printed image and had insufficient light resistance.

From the results of the above light resistance test, the edible dye contains Blue No. 1, the fixing agent contains disaccharide having a solubility in 100 ml of water at 20 ° C. in the range of 20 g or more and 39 g or less, and water and propylene as solvents. It was found that an inkjet ink containing at least one of glycol or ethanol sufficiently suppresses the photo-fading of the printed image and imparts excellent light resistance.

Further, as shown in Table 1, in the inkjet inks of Examples 1 to 13, the evaluation results of the intermittent resumption were all “Δ” or higher, and it was found that the ink jet inks had excellent light resistance and sufficient intermittent resumption. rice field. In particular, in Example 5, the blending ratio of the coloring material is the upper limit (15% by mass), and in Example 8, the blending ratio of the fixing agent is the upper limit (20% by mass). It can be seen that sex is maintained.

Further, as shown in Table 1, in the inkjet inks of Examples 1 to 13, the evaluation results of transfer resistance (tablet drying property) were all “Δ” or higher, and the tablet drying property was sufficient as well as excellent light resistance. Was found to have.

The scope of the present invention is not limited to the exemplary embodiments illustrated and described, but also includes all embodiments that provide an equivalent effect to that of the present invention. Further, the scope of the present invention is not limited to the combination of the features of the invention defined by the claims, but may be defined by any desired combination of the specific features of all the disclosed features.

1 Tablet substrate 1S Surface 3 Printed image 4 Specified dye 5 Unlocked printed matter 7 Film-coated layer 9 Film-coated tablet printed matter 11 Uncoated printed image (solid image)
13 Film-coated lock print image (two-dimensional bar code)

In order to achieve the above object, the inkjet ink according to one aspect of the present invention contains the largest amount of blue No. 1 as an edible dye, and has a solubility as a fixing agent in 100 ml of water at 20 ° C. within a range of 20 g or more and 39 g or less. When the solvent contains water and at least one of propylene glycol or ethanol and the solvent contains the propylene glycol, the amount of the propylene glycol added is the total mass of the ink. On the other hand, when the amount is 2% by mass or more and the solvent contains the ethanol, the amount of the ethanol added is 6.5% by mass or more with respect to the total mass of the ink .

Claims (10)

Contains Blue No. 1 as an edible dye,
The fixing agent contains a disaccharide having a solubility in 100 ml of water at 20 ° C. in the range of 20 g or more and 39 g or less.
An inkjet ink characterized by containing water and at least one of propylene glycol or ethanol as a solvent. The inkjet ink according to claim 1, wherein the fixing agent contains reduced isomaltulose. The inkjet ink according to claim 1 or 2, wherein the solvent further contains at least one of glycerin and isopropyl alcohol. The inkjet according to any one of claims 1 to 3, wherein the blending ratio of the edible dye is in the range of 1% by mass or more and 15% by mass or less with respect to the total mass of the ink. ink. The inkjet according to any one of claims 1 to 4, wherein the blending ratio of the fixing agent is in the range of 1% by mass or more and 20% by mass or less with respect to the total mass of the ink. ink. The solvent contains the propylene glycol.
The inkjet according to any one of claims 1 to 5, wherein the amount of propylene glycol added is in the range of 2% by mass or more and 40% by mass or less with respect to the total mass of the ink. ink. The inkjet ink according to claim 6, wherein the amount of propylene glycol added is 10% by mass or more with respect to the total mass of the ink. The solvent contains the ethanol.
The one according to any one of claims 1 to 7, wherein the amount of ethanol added is in the range of 6.5% by mass or more and 40% by mass or less with respect to the total mass of the ink. Inkjet ink. A tablet comprising a printing unit printed using the inkjet ink according to any one of claims 1 to 8. The tablet according to claim 9, which is a medical tablet.

Images